1. Field of the Invention
The present invention relates to a magnetic transfer method in which a magnetic transfer master carrier having pattern-shaped projections and recesses for transferring information to a magnetic recording medium is used, and a magnetic transfer device equipped with the magnetic transfer master carrier.
2. Description of the Related Art
In general, with the increase in information content, inexpensive media having a large-capacity for recording a large amount of information and preferably providing so-called quick access capable of reading a required point within a short time are desired with regard to a magnetic recording medium. For example, high-density magnetic recording media which are flexible disks such as hard disks or ZIPs (Iomega Corporation) have been known. In these high-density magnetic recording media, information recording areas are constituted of narrow tracks. In order to accurately scan a narrow track width by a magnetic head and reproduce a signal at a high S/N, a so-called tracking servo technology plays an important role.
Servo information including servo signals for track positioning, address signals for the tracks, and reproduction clock signals need to be recorded beforehand as a pre-format on a magnetic recording medium when the magnetic recording medium is fabricated. As a method of accurately and efficiently perform this pre-format, a method of transferring a pattern which is formed in a master carrier and which holds servo information to a magnetic recording medium by magnetic transfer is proposed in, for example, Patent Literatures 1 and 2 and the like.
In magnetic transfer, a magnetic pattern corresponding to an information pattern owned by a master carrier is magnetically transferred to a slave medium by applying a transfer magnetic field in the state where the master carrier holding the information to be transferred is in tight contact with the magnetic recording medium (slave medium) such as a magnetic disk medium. Magnetic transfer has the following advantages: recording can be statically performed without changing the relative positions of the master carrier and the slave medium; accurate pre-format recording can be performed; and the time required for recording is extremely short.
Patent Literature 1
Japanese Unexamined Patent Publication No. 63(1988)-183623
Patent Literature 2
U.S. patent Laid-Open No. 20020075583
In magnetic transfer, how uniformly signal recording can be performed over the entire surface of a disk, and how many slave media can be subjected to magnetic transfer using one master carrier, are very important subjects.
In order to perform uniform signal recording, a tight contact pressure is required up to such a degree that the master carrier and the slave medium can be uniformly brought into tight contact with each other over the entire surfaces. Meanwhile, according to research by the present inventors, it has become clear that the deformation of the master carrier and pattern breakage tend to occur as this tight contact pressure increases. Moreover, it has also become clear that the occurrence of the deformation of the master carrier and pattern breakage depends not only on the tight contact pressure but also on elastic characteristics of a substrate of the master carrier, the thickness of the substrate, the pattern area and layout, and the like.
Therefore, in order to realize uniform signal recording and magnetic transfer to more slave media, it is considered to be necessary that a substrate thickness, pattern area and layout, and the like be designed by taking elastic characteristics of the substrate of the master carrier into consideration, and that the setting of the tight contact pressure between the master carrier and the slave medium be optimized.